NGC 1851 is an ancient globular star cluster some 40,000 light-years from our Sun. All globular star clusters have a very high density of stars. “Peering deep into them to look at the faintest stars requires high spatial resolution. It’s essential,” said Principal Investigator Alan McConnachie of Canada’s Dominion Astrophysical Observatory (formerly the Herzberg Institute of Astrophysics), who wants to obtain a better understanding of the cluster’s stellar population –– particularly of its age, any evidence for multiple stellar populations, and the distribution of low mass stars. “We want to push the capabilities of GeMS to the limit so that we can determine the internal dynamics of globular clusters and understand how best to use MCAO for precision astrometry and photometry,” he said. “After all, MCAO is a key capability for the future of ground-based astronomy through its use in the Thirty Meter Telescope, and GeMS is allowing us to peek into that future and get a head start!”